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  1. #1
    Join Date
    Jun 2006
    Posts
    247

    probe false trigger

    I rapid to within .5" for a Z-probe, then the next line is:
    M78 G31 Z.05 F60.

    The M78 alarms out if the probe touches something when it shouldn't
    but Im getting the alarm even when its not touching anything, before it even starts moving

    Its an intermittant problem that came and went a couple times today
    It makes me wonder if the contacts in the probe are dirty to the point that its causing this

  2. #2

    Probe distance

    I have a Renishaw Wireless probe on my HAAS TM-1P.

    The instructions in the book and on the screen tell you to get within .4 of the part with the probe. It you are at .5 it may be alarming out due to not touching something within the .4 requirement. This has happened to me on occasion.

    If you have the wireless probe you may also want to check the batteries. It will act crazy when the batteries get low.

    Just a couple of things you might want to look at.

    John

  3. #3
    Join Date
    Jan 2007
    Posts
    1389
    JOhn I belive Kendo wrote the probe macro for that, thats why it will work for him at .500. unless he didnt make some changes somewhere.
    http://www.cnczone.com/forums/showthread.php?t=82547

    Kendo did you get alarms on your x setting in this thread?
    http://www.cnczone.com/forums/showthread.php?t=82547 post number 8 ?

    I am going to try that sample you and pit202 posted this week

    Delw

  4. #4
    Join Date
    Jun 2006
    Posts
    247
    John, Delw is right, Im using my own custom routine so Its set to do what I want

    Delw, I was running another macro when this alarm problem popped up yesterday

    My center probing macro from the other thread always runs fine when I use it, but so did my Z probing macro up until yesterday

    I switched back to the renishaw Z-probe just to make sure it wasn't something with my macro, but I got "probe open" alarm when I did that

    This morning, I come in and push the button and all macros run fine with no false triggers again

  5. #5
    Join Date
    Jan 2007
    Posts
    1389
    Kendo, I dont know much about probes or the marcos and wont pretend to however, I notice that when the techs made some change's in some of the parameters that they would power the machine down and power it back on. could it be the same deal you need to power off reboot(power on) for them to take effect?

    did you power off yesterday after making your changes? if not maybe thats what happened today you powered off yesterday when you were done then this morning came in powered up and the system then reconized the changes you made ???

    Delw

  6. #6
    Join Date
    Jun 2006
    Posts
    247
    I didnt make any changes

    I was running a custom Z-probe macro thats been running on this machine without incident for over 6 months

    It started this intermittant false trigger out of the blue and it makes me think the probe might be in need of some TLC

    The environment the machine lives in is quite nasty, and its a gantry router with the tool changer hanging out in the open

  7. #7
    Join Date
    Nov 2003
    Posts
    236

    Dwell

    Put a short dwell before this. Maybe G4 P.5

    Quote Originally Posted by kendo View Post
    I rapid to within .5" for a Z-probe, then the next line is:
    M78 G31 Z.05 F60.

    The M78 alarms out if the probe touches something when it shouldn't
    but Im getting the alarm even when its not touching anything, before it even starts moving

    Its an intermittant problem that came and went a couple times today
    It makes me wonder if the contacts in the probe are dirty to the point that its causing this

  8. #8
    Join Date
    Jun 2006
    Posts
    247
    uhh, ok

    should I put dwells everywhere there's a transition from rapid to feed-till-skip?

    You've got me wonderin whats going on with this...

    is the motion stop at the end of the rapid causing the stylus to rebound?

  9. #9
    Join Date
    Jul 2007
    Posts
    52

    Smile

    Quote Originally Posted by kendo View Post
    I didnt make any changes

    I was running a custom Z-probe macro thats been running on this machine without incident for over 6 months

    It started this intermittant false trigger out of the blue and it makes me think the probe might be in need of some TLC

    The environment the machine lives in is quite nasty, and its a gantry router with the tool changer hanging out in the open
    Any time we get a problem with a probe (probe open alarm) program that has been running OK before hand we change the batteries. The only other problem we had once was with the power supply to the Renishaw control unit in the cabinet.

    Andrew.
    VF3+TRT210, VF3, VF2+HRT160, VF2SS+TR160, VF2SS+TR160, VF5TR, VF5TR, VF2SS+HRT-210HSHS,VF2SS+HRT-210HSHS,VF2SS+HRT-210HSHS

  10. #10
    Join Date
    Nov 2003
    Posts
    236

    Mode change

    If I get you right - you rapid, then feed 'til skip. On the Haas a mode change will cause exact stop. This brief stop may just shake the probe enough to cause a trigger. If this is the cause a short dwell should resolve it. I said to use a 1/2 second dwell but you may be able to go a 1/4 dwell.

    This is just a shot in the dark based on what you had said.

    Quote Originally Posted by kendo View Post
    uhh, ok

    should I put dwells everywhere there's a transition from rapid to feed-till-skip?

    You've got me wonderin whats going on with this...

    is the motion stop at the end of the rapid causing the stylus to rebound?

  11. #11
    Join Date
    Jul 2008
    Posts
    47
    If default smoothness is set to finish, this can make an open probe alarm in z measurements. It happened to me once between jobs and the probe would fully calibrate and measure in any axis but z. Worth a shot. I'd say the dwell is a good move, but since you said that this happens even with the haas macro, I'd lean toward the smoothness setting. I don't know what # it is, but it's next to setting 85 "max corner rounding".

    Greg

  12. #12
    Join Date
    May 2006
    Posts
    183
    I'm having this same problem.

    I just sat down and wrote my very first "custom" probe cycle, since I got tired of jogging the probe into position and manually executing the probing cycles.

    My code is as follows, for measuring a bore:

    T20 M06
    G54 X0. Y0.
    G43 H20 Z1.0
    G65 P9832
    G65 P9810 Z-1.375 F100.
    G65 P9814 D0.750 S54
    G65 P9810 Z1.0
    G65 P9833
    G28 G91 Z0.

    It gets through the first 4 lines ok, then on the 5th it alarms out telling me it's path is obstructed, when it's clearly come nowhere near any kind of obstacles.

    Kendo, did you ever figure out how to resolve your problem?

  13. #13
    Join Date
    Jun 2006
    Posts
    247
    I dont use those macros from the renishaw manual,
    But Im pretty sure you need to limit your look-ahead with
    G103 P1
    put that just before the protected positioning P9810 line

  14. #14
    Join Date
    May 2006
    Posts
    183
    Doesn't seem to have done the trick... I guess I'll call Renishaw on Monday.

  15. #15
    Join Date
    Apr 2005
    Posts
    713
    Cory, it's been a while since I've looked at this stuff and I'm not in my shop right now: I notice on the 5th line of code you're specifiying a feedrate. I've never done that and can't help but wonder if that's part of the problem. What is the default fast feedrate? Also, are you in exact-stop mode? I'm just thinking that something is jerking enough when the Z starts to move down that it's bouncing the stylus enough to trigger the probe. Just a guess though.

    Also, to verify what you allready found, look ahead has never been a problem for me.

  16. #16
    Join Date
    May 2006
    Posts
    183
    Quote Originally Posted by Matt@RFR View Post
    Cory, it's been a while since I've looked at this stuff and I'm not in my shop right now: I notice on the 4th line of code you're specifiying a feedrate. I've never done that and can't help but wonder if that's part of the problem. What is the default fast feedrate? Also, are you in exact-stop mode? I'm just thinking that something is jerking enough when the Z starts to move down that it's bouncing the stylus enough to trigger the probe. Just a guess though.

    Also, to verify what you allready found, look ahead has never been a problem for me.
    I was basing my code off the example renishaw provides in their inspection plus manual, which includes a feedrate, so I think that shouldn't be an issue.

    I just shut the machine down for the night, so I'll have to check on exact stop tomorrow and see if that makes a difference.

    Thanks for the suggestions

  17. #17
    Join Date
    Jun 2006
    Posts
    247
    page 6 of the manual gives an example almost exactly like Cory's, with the look-ahead limited,
    then the next paragraph says you don't need it!
    so my bad for not reading further

    I don't think the exact stop is an issue
    you rapid to Z1.0, then turn the probe on
    that should give plenty of time until the protected move on the next line
    the P9832 makes the spindle orient, then settings check, and re-check...
    it takes a couple seconds so that should be plenty of time

    I tried to run your code and it wouldnt work until I changed
    S54 to S1.
    in the renishaw macros, G54-G59 corresponds to S1.-S6.
    try that next

  18. #18
    Join Date
    Jun 2006
    Posts
    247
    one more thing,
    make sure the line of sight is never broken between the spindle probe and the reciever, wherever its mounted at on your machine
    that had me scratchin my head this morning
    when it happens its not like theres an alarm saying "line of sight has been broken"
    no, it just says "skip signal found"
    which would cause your "path obstructed" alarm too

  19. #19
    Join Date
    May 2006
    Posts
    183
    Quote Originally Posted by kendo View Post

    I tried to run your code and it wouldnt work until I changed
    S54 to S1.
    in the renishaw macros, G54-G59 corresponds to S1.-S6.
    try that next
    Interesting. I assumed that the work offsets worked the same as in the quick code macros for probing. I guess not.

    Quote Originally Posted by kendo View Post
    one more thing,
    make sure the line of sight is never broken between the spindle probe and the reciever, wherever its mounted at on your machine
    that had me scratchin my head this morning
    when it happens its not like theres an alarm saying "line of sight has been broken"
    no, it just says "skip signal found"
    which would cause your "path obstructed" alarm too
    I was thinking about this yesterday as well. It's certainly possible. My receiver seems to be mounted fairly high, and I've had problems before with this, from time to time.

    Thanks for the advice Kendo.

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